Tailings derived from mining operations, such as oil sands mining, are often placed in dedicated disposal ponds for settling.
The settling of fine solids from the water in tailings ponds is a relatively slow process. Certain techniques have been developed for dewatering fine tailings. Dewatering of thick fine tailings can include contacting the thick fine tailings with a flocculant and then depositing the flocculated fine tailings in a deposition area where the deposited material can release water and eventually dry.
There are several factors that may influence the performance of dewatering operations. For instance, inadequate dispersion of the flocculant into the thick fine tailings can decrease the efficiency of the flocculating agent and the overall dewatering. Inadequate mixing may also result in inefficient use of the flocculating agents, some of which remain unmixed and unreacted resulting in higher flocculant dose requirements to achieve optimally dosed conditions.
In the context of dewatering thick fine tailings, there are a number of challenges related to flocculant addition and handling of the resulting flocculation mixture.